2. UTI :INTRODUCTION
Urinary tract infection is the presence of
microbial pathogens in the normally sterile
urinary tract.
Infections are overwhelmingly bacterial although
fungi(various species of Candida),viruses(e.g. JC
virus, Adenoviruses) and parasites may cause
UTI.
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3. UTI :INTRODUCTION
The urinary tact is normally sterile and sterility
is maintained by
-- The urinary flow rate
-- Rapid bladder emptying
-- Mounting of an active inflammatory response
by WBC and
-- Antimicrobial peptides secreted by the
epithelium : defensins and cathelcidins
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4. UTI:EPIDEMIOLOGY A group of diverse disorders that together constitute
the most common bacterial infection affecting humans.
Primarily an infection of females with males affected
at the two extremes of life
In sexually active women incidence of 0.5-0.7 per year.
60% will have at least one UTI in their lifetime.
UTIs may involve deep tissue infection or be confined
to the bladder mucosa.
90% of infections in males involve deep tissue invasion
and >70% of infections in women are superficial
infections. 4
5. UTI:EPIDEMIOLOGY(CONT’D)
UTIs may be symptomatic or asymptomatic,
complicated or uncomplicated.
Upper tract( above vesicouretral junction) or lower
tract
Asymptomatic UTI is isolation of bacteria in urine in
quantitative amounts consistent with infection but
without localizing GU 0r systemic signs or symptoms.
Complicated UTI refers to UTI in the presence of
structural or functional abnormalities of the urinary
tract.(includes those with UTI following
instrumentation)
Enterobacteriace the most common pathogens with
E.coli accounting for most infections.
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6. UTI:PATHOGENESIS
The ascending route the most common route of
infection(>95%).Organisms originate from the
gut flora, colonize the vagina& periurethral area
and ascend into the bladder.
Bacterial virulence factors and host factors
determine whether infection is sustained.
Gender is a major determinant of incidence.
Uropathogenic E.coli have virulence properties
that mediate key steps: sustained intestinal
carriage, persistence in the vagina and ascension
and invasion of the urinary tract.
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7. UTI:PATHOGENESIS(CONT’D)
Virulence properties include the O
antigen,K
antigen,hemolysins,adhesins,etc
Adhesins mediate attachment and
adherence via specific uroepithelial
receptors. P fimbriae the most studied
adhesins and bind to receptors in the
vagina,urinary tract, kidneys and large
intestine. The receptors are identical to
the glycosphingolipids of the P blood
group system.
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8. UTI:PATHOGENESIS(CONT’D)
Host factors in the pathogenesis include
1.Normal vaginal flora: lactobacilli in particular.
2. Normally functioning bladder: elimination by
voiding.
3.Ability to secret blood group antigens.
4.Competent ureterovesical junction.
Sexual activity is strongly correlated with UTI.
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9. UTI:PATHOGENESIS(CONT’D)
Conditions that promote occurrence of
UTI or amplify clinical impact include
1.Impedenace of urinary flow :anatomic or
functional obstruction.
2.Vesicoureteral reflux: predisposes
spread to kidney and with UTI causes
renal damage, more important in children
3. Foreign bodies e.g. Indwelling catheters
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10. UTI: CLINICAL MANIFESTATIONS
UTIs maybe asymptomatic.
Lower tract UTI symptoms include
dysuria,frequency and suprapubic pain.
Upper tract UTI symptoms include flank
pain,fever/chills,nausea/vomiting and CVA
tenderness.
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11. UTI: DIAGNOSIS
Culture of urine collected through
suprapubic aspiration the gold standard
for diagnosis.
Quantitative urine culture of clean catch
urine the next best to distinguish between
true infection and contamination.
Morning specimen preferable.
In a young woman with typical symptoms
and pyuria the constellation of symptoms
may be diagnostic of UTI and culture may
not need to be done. 11
12. UTI :DIAGNOSIS(CONT’D)
Standard definition of a positive urine culture is
> 100,000 CFU/ml.
Acute, uncomplicated UTI in women: 100,000
CFU/ml has a specificity of 99% but sensitivity of
51%.1000 CFU /ml has a sensitivity of 80% and
specificity of 90% and is a more appropriate
criterion.
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13. UTI :DIAGNOSIS(CONT’D)
Acute urethral syndrome (symptomatic
abacteruria)in women :probably an early
variant of acute uncomplicated UTI.
>1000CFU/ml with the usual
uropathogens may suffice to make a
diagnosis,
Acute uncomplicated pyelonephritis in
women:> 1000 CFU/ml of a single
uropathogen makes the diagnosis.
UTI in men:>10,000CFU/ml offers a
sensitivity and specificity of >90%. 13
14. UTI :DIAGNOSIS(CONT’D)
Particular infections: Infections due to
Staphylococcus saprophyticus and
Candida usually have organisms between
100 to 10,000 CFU/ml.
In the adult with urinary symptoms
pyuria correlates closely with
UTI.Leucocyte esterase activity a good
screening test for pyuria(75-96%
sensitivity in symptomatic patients).
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15. UTI :DIAGNOSIS(CONT’D)
WBC >10/mm in unspun urine in a counting
chamber highly correlates with true
infection.Pyuria as defined by micro exam of
spun urine gives many false positives and false
negatives.
1 or more organisms per oil immersion field with
Gram stain of unspun urine highly correlates
with significant pyuria.
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16. UTI : TREATMENT
• Decisions on treatment (duration/specific
antibiotic) depend on the syndrome i.e. lower
vs upper tract UTI, susceptibility pattern of
organisms, history of drug allergy.
• Acute ,uncomplicated UTI in women:
Therapy has 3 objectives;
• 1)Eradication of lower UTI that is producing
symptoms
• 2)identifying those with silent upper
UTI(~30%)
• 3)eradication of organism from vaginal and
GI reservoirs. 16
17. UTI : TREATMENT(CONT’D)
Acute, uncomplicated UTI in women: The
cornerstone of therapy is a short course(3 days) of
treatment with TMP-SMX,TMP or a
fluoroquinolone.(N.B.TMP-SMX not to be used in
areas with > 20% resistance to it by E.coli)
If patient is asymptomatic after therapy no
further action.
If patient is symptomatic & pyuric and bacteruric
extended treatment for 10-14 days.
If patient symptomatic, pyuric and no bacteruria
look for Chlamydia, fungal infections, etc
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18. UTI : TREATMENT(CONT’D)
• Acute pyelonephritis in women: these
patients have an invasive infection and are at
risk of bacteremia. Goals of therapy are:
• 1)control of possible urosepsis
• 2)eradication of the invading organism and
• 3) prevention of recurrences.
• Initial treatment must achieve immediate
control and should have a >99% probability of
success and : a floroquinolone, a β
lactam/aminoglycoside combination or an
advanced spectrum β lactam can be
prescribed.
• Usually treatment is IV. 18
19. UTI : TREATMENT(CONT’D)
After control of sepsis oral treatment with
TMP-SMX or floroquinolone to complete a
14 day course.
UTI in pregnancy: screening and
treatment for asymptomatic UTI justified.
Urine culture recommended at 12-16
weeks. Limited drug choice because of
toxicity, continuing follow-up is a must.
Ampicillin, cephalosporins,
sulphonamides (except near term) can be
used. Avoid floroquinolones. 19
20. UTI : TREATMENT(CONT’D)
Recurrent UTI in women : Reinfection vs
relapse.
Relapse is recurrence with the same organism as
the pretherapy isolate whereas reinfection is
recurrence with a different organism
Most recurrences are reinfections.First steps to
prevent reinfections include ‘
i)Voiding after intercourse & changing
contraceptive practice
ii) Estrogen replacement (local or systemic) in
postmenopausal women and use of cranberry or
blueberry juice.
In those with recurrent infection after treatment
lasting <14 days it may indicate presence of a
sequestered focus(relapse) One attempt of
extended treatment i.e. 4-6 wks can be made. 20
21. UTI : TREATMENT(CONT’D)
• In those with recurrent reinfection in spite of
non-antimicrobial measures:
1) Low dose long term prophylaxis TMP-SMX or
floroquinolone
2)Single dose post coital treatment
3)Self- initiated short course treatment with onset
of symptoms.
Vaccines to prevent infection and probiotics to
restore the normal vaginal flora are under
investigation.
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22. UTI : TREATMENT(CONT’D)
UTI in men: should always be assumed to mean
tissue invasion of the prostate, kidney or both.
Risk factors include lack of circumcision, anal
intercourse and acquisition from a sexual
partner.
Standard treatment is 10-14 days of TMP-SMX
or floroquinolone.
In those with recurrent infection after an
appropriate course of treatment urologic
evaluation as well as extended treatment(4-
6wks) required.
Prostatic infection particularly difficult to
eradicate.
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23. UTI : TREATMENT(CONT’D)
Complicated UTI :indicates presence of
structural or functional urinary tract
defects. The range of organisms is greater
and resistance to antimicrobials is
common.
Asymptomatic patents not to be treated
with the exception of those scheduled to
undergo UT manipulation:
For the acutely septic, IV broad spectrum
antibiotics and oral floroquinolones for the
less ill. 23
24. UTI : TREATMENT(CONT’D)
Correct the UT abnormality in conjunction with
measures to correct the abnormality.
If abnormality is corrected 4-6 wks of “curative”
treatment to follow.
If correction is not possible shorter courses aimed
at controlling symptoms reasonable.
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25. THANK YOU FOR YOUR ATTENTION!!!
ANY QUESTION YOU WELL COME?
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